Enterasys D-Series - Chapter 16: DHCP Server Configuration; DHCP Overview

Enterasys D-Series CLI Reference 16-1
16
DHCP Server Configuration
ThischapterdescribesthecommandstoconfiguretheIPv4DHCPserverfunctionalityonaD‐
Seriesswitch.
DHCP Overview
DynamicHostConfigurationProtocol(DHCP)forIPv4isanetworklayerprotocolthat
implementsautomaticormanualassignmentofIPaddressesandotherconfigurationinformation
toclientdevicesbyservers.ADHCPservermanagesauser‐configuredpoolofIPaddressesfrom
whichitcanmakeassignmentsuponclientrequests.A
relayagentpassesDHCPmessages
betweenclientsandserverswhichareondifferentphysicalsubnets.
DHCP Server
DHCPserverfunctionalityallowstheD‐SeriesswitchtoprovidebasicIPconfiguration
informationtoaclientonthenetworkwhorequestssuchinformationusingtheDHCPprotocol.
DHCPprovidesthefollowingmechanismsforIPaddressallocationbyaDHCPserver:
• Automatic—DHCPserverassignsanIPaddresstoaclientfor
alimitedperiodoftime(or
untiltheclientexplicitlyrelinquishestheaddress)fromadefinedpoolofIPaddresses
configuredontheserver.
•Manual—Aclient’sIPaddressisassignedbythenetworkadministrator,andDHCPisused
simplytoconveytheassignedaddresstotheclient.Thisismanagedby
meansof“static”
addresspoolsconfiguredontheserver.
TheamountoftimethataparticularIPaddressisvalidforasystemiscalledalease.TheD‐Series
maintainsaleasedatabasewhichcontainsinformationabouteachassignedIP address,theMAC
addresstowhichitisassigned,the
leaseexpiration,andwhethertheaddressassignmentis
dynamic(automatic)orstatic(manual).TheDHCPleasedatabaseisstoredinflashmemory.
InadditiontoassigningIPaddresses,theDHCPservercanalsobeconfiguredtoassignthe
followingtorequestingclients:
•Defaultrouter(s)
•DNSserver(s)anddomainname
•NetBIOSWINSserver(s)
andnodename
For information about... Refer to page...
DHCP Overview 16-1
Configuring General DHCP Server Parameters 16-3
Configuring IP Address Pools 16-11